Consolidated Statements of Cash Flows - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Cash flows from operating activities:
Net loss including noncontrolling interests in subsidiaries	$ (17,129,000)	$ (104,848,000)
Adjustments to reconcile net loss including noncontrolling interests in subsidiaries to net cash provided by (used in) operating activities:
Change in fair value of investment, net (Note 6)	(9,899,000)	59,103,000
Loss on sale of investment (Note 6)	9,230,000	19,095,000
Impairment of other investment (note 6)	8,195,000	1,000,000
Gain on disposal of other investment (Note 6)	(2,000,000)	0
Depreciation and amortization	3,227,000	27,145,000
Change in fair value of Series A redeemable convertible preferred stock embedded derivative	(3,258,000)	0
Change in fair value of Series A warrant	(1,260,000)	0
Non-cash stock compensation	1,075,000	(317,000)
Change in value of trading securities	(2,241,000)	0
Impairment of patent-related intangible assets	0	28,210,000
Other	0	(436,000)
Changes in assets and liabilities:
Accounts receivable	32,373,000	(28,189,000)
Prepaid expenses and other assets	(220,000)	(208,000)
Accounts payable and accrued expenses	109,000	963,000
Royalties and contingent legal fees payable	(20,510,000)	19,359,000
Net cash provided by (used in) operating activities	(2,308,000)	20,877,000
Cash flows from investing activities:
Patent acquisition costs	(4,420,000)	0
Sale of investment at fair value (Note 6)	6,628,000	19,097,000
(Purchase) Sale of other Investments (Note 6)	2,000,000	(7,000,000)
Purchases of trading securities	(147,178,000)	(102,769,000)
Maturities and sales of trading securities	75,090,000	66,640,000
Purchases of property and equipment	(183,000)	(34,000)
Net cash provided by (used in) investing activities	(68,063,000)	(24,066,000)
Cash flows from financing activities:
Repurchase of common stock	0	(4,634,000)
Repurchase of restricted common stock	0	(229,000)
Issuance of redeemable convertible preferred stock and Series A warrants, net of issuance costs	33,842,000	0
Proceeds from exercise of stock options	79,000	257,000
Net cash provided by (used in) financing activities	33,921,000	(4,606,000)
Decrease in cash and cash equivalents and restricted cash	(36,450,000)	(7,795,000)
Cash and cash equivalents and restricted cash, beginning	128,809,000	136,604,000
Cash and cash equivalents and restricted cash, ending	$ 92,359,000	$ 128,809,000